The present invention relates to an apparatus for the manufacture of clear ice pieces, particularly for use with a refrigerator or freezer unit including a cooling circuit having a coolant source at a very low temperature, the apparatus including a finger-type chilling member adapted to be positioned within a tank containing water to be caused to flow to wash around the member and adapted to be thermoconductively connected to the coolant source to be cooled thereby such that the water freezes on the member in the form of a clear ice piece, and a heating device operatively connected to the member to selectively heat the member to detach therefrom an ice piece formed thereon. The present invention also relates to a system for manufacturing clear ice pieces, such system including a refrigerator or freezer unit including a cooling circuit having an evaporator and a coolant source at a very low temperature, as well as one or more of the above discussed apparatus. Yet further, the present invention relates to a control system for controlling the temperature of the finger-type chilling member of such an apparatus.
German Registered Utility Model No. 88 12 951 and German Patent Specification No. 38 35 132 describe a device for the manufacture of clear ice pieces, wherein a water flow is generated such that water moves back and forth within a tank, such tank being moved by a swinging drive mechanism whereby the water flow washes about finger-type chilling devices which project into the tank. Such chilling devices are thermoconductively connected to a refrigerant line of a cooling device, such that ice pieces freeze and are formed on the chilling devices. In this known device, the ice formation is achieved specifically from the finger-type chilling devices. A tilting tank with a residual water storage container is disclosed in German Patent Specification No. 32 16 597. Also, the detachment of the hollow ice pieces frozen tightly to such finger-type chilling devices is known to be achieved by heating the finger-type chilling devices. Heating of ice pieces formed in individual compartments of a tank to detach them after completion of the freezing process is disclosed in European Patent Specification No. 0 333 887.
German Patent Specification No. 33 14 056 discloses a freezer unit, particularly a freezer cabinet, in which an evaporation system or evaporator is subdivided into at least two evaporation sections allocated to respective thermally separated compartments of the cabinet. At least one of these evaporation sections can be bridged by a controllable bypass feeder, and an additional evaporator is allocated to the bridged evaporation section, the effective surface of such additional evaporator being substantially less than that of the bridged evaporation section. This arrangement is intended to compensate for disadvantages that arise due to fluctuating load status and unit capacity factor by economical adjustment of the evaporation output to the load status. Switching is effected by three-way solenoid valves. Switching of refrigerant flow between two evaporators: each of which is individually connected, is disclosed in German Patent Specification No. 30 24 590. Therein is disclosed a domestic refrigerator or freezer unit in which, in addition to a compartment for storing refrigerated products, there is an additional section for preparing chilled drinking water. One evaporator is allocated to the refrigerated products compartment and the other evaporator is allocated to the additional section for storing chilled drinking water.